<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>react的生命周期（旧）</title>
</head>
<body>
  <div id="test"></div>
  <!-- 引入库：先引入核心库，再引入操作DOM的扩展库 -->
  <script type="text/javascript" src="../js/react.development.js"></script>
  <script type="text/javascript" src="../js/react-dom.development.js"></script>
  <!-- 将jsx转为js -->
  <script type="text/javascript" src="../js/babel.min.js"></script>
  <script type="text/babel">    //必须写babel，因为默认js
/*
    1.  初始化阶段：由ReactDOM.render()触发---初次渲染
        1. constructor()
        2. componentWillMount()
        3. render()
        4. componentDidMount()   ====>   常用，一般在这个钩子中做初始化的事，例如：开启定时器、发送网络请求、订阅消息

    2.  更新阶段：由组件内部React.setState()或父组件重新render触发
        1. shouldComponentUpdata()
        2. componentWillUpdata()
        3. render()     ======>     必用
        4. componentDidUpdata()

    3.  卸载组件：由ReactDOM.unmountComponentAtNode()触发
        1. componentWillUnmount()   ===>   常用，一般做收尾的事，例如：关闭定时器、取消订阅消息
*/

    class Count extends React.Component{
      state = {count:0}

      add = ()=>{
        const {count} = this.state
        this.setState({count:count+1})  //这里不属于修改，而是状态更新
      }

      //卸载组件按钮的回调
			death = ()=>{
				ReactDOM.unmountComponentAtNode(document.getElementById('test'))
			}

			//强制更新按钮的回调
			force = ()=>{
				this.forceUpdate()
			}

			//组件将要挂载的钩子
			componentWillMount(){
				console.log('Count---componentWillMount');
			}

			//组件挂载完毕的钩子
			componentDidMount(){
				console.log('Count---componentDidMount');
			}

			//组件将要卸载的钩子
			componentWillUnmount(){
				console.log('Count---componentWillUnmount');
			}

			//控制组件更新的“阀门”
			shouldComponentUpdate(){
				console.log('Count---shouldComponentUpdate');
				return false
			}

			//组件将要更新的钩子
			componentWillUpdate(){
				console.log('Count---componentWillUpdate');
			}

			//组件更新完毕的钩子
			componentDidUpdate(){
				console.log('Count---componentDidUpdate');
			}

			render(){
				console.log('Count---render');
				const {count} = this.state
				return(
					<div>
						<h2>当前求和为：{count}</h2>
						<button onClick={this.add}>点我+1</button>
						<button onClick={this.death}>卸载组件</button>
						<button onClick={this.force}>不更改任何状态中的数据，强制更新一下</button>
					</div>
				)
			}
		}

    class A extends React.Component{
      state = {car:'大众'}

      upCar = ()=>{
        const {car} = this.state
        this.setState({car:'小米'})
      }

      render(){
        return (
          <div>
            <div>我是A组件</div>
            <button onClick={this.upCar}>换车</button>
            <B car={this.state.car}/>
          </div>
        )
      }
    }

    class B extends React.Component{
      render(){
        return(
          <div>目前驾驶的车：{this.props.car}</div>
        )
      }
    }


    ReactDOM.render(<A/>, document.getElementById('test'))
  </script>
</body>
</html>